Discovery endpoints
Use discovery endpoints to inspect supported formats, options, limits, and extractor metadata.
Options for one format
GET /options/{format}
X-Fast-Api-Key: YOUR_API_KEYUse this endpoint when you are building a /estimate, /extract, or /transcribe request body. It returns the valid selectedCapabilities values and capabilityOptions keys allowed for that source format.
The response always includes a constraints array. An empty array means the advertised capabilities are independent. Clients must apply every published dependency or mutual-exclusion constraint before submitting a job.
For example, GET /options/mp4 returns video.audio, video.metadata, video.subtitles, video.frames, and media.transcript. If you select media.transcript, use the returned transcription.mode option and one of its allowed values.
{
"format": "mp4",
"job": "extract.mp4",
"defaults": {
"selectedCapabilities": ["video.audio", "video.frames", "video.metadata", "video.subtitles"],
"includeManifest": true,
"capabilityOptions": {
"video.audio": {
"audioFormat": "mp3"
},
"video.frames": {
"frameMode": "evenly-spaced",
"frameIntervalSeconds": 1,
"maxExtractedFrames": 500
}
}
},
"capabilities": [
{
"id": "media.transcript",
"output": "transcript",
"defaultSelected": false,
"options": [
{
"id": "transcription.mode",
"type": "enum",
"required": true,
"defaultValue": "fast",
"allowedValues": ["fast", "quality", "meeting-intelligence"]
}
]
}
],
"constraints": []
}List extractors
GET /extractors
X-Fast-Api-Key: YOUR_API_KEYReturns registered extractors with source formats, categories, costing metadata, and limits.
Source file type
GET /extractors/{sourceFileType}Use this when you want extractor metadata for one source extension. For example, GET /extractors/mp4 returns the Extract jobs that accept MP4 input. Use GET /options/mp4 when you need to construct the actual selectedCapabilities and capabilityOptions payload.
Schema
GET /schema
X-Fast-Api-Key: YOUR_API_KEYReturns a compact supported-format schema for API clients that only need extension and output-group discovery. Prefer GET /options/{format} when you need to construct a valid options payload.
Public discovery scope
Use the documented discovery endpoints on this page when building API clients.